Safety in the Skies

Avoiding Blood Clots When Flying

Jun 1, 2002

The biggest risk to athletes flying to events is not terrorists but blood clots. A recent victim was Tim Hentzel, 26, a competitive triathlete stricken after a flight from Minneapolis to San Francisco. Other examples are Pamela Nimmo, 23, Scotland's leading female squash player, who suffered a clot in the lung after a 10-hour flight, and Shawn Blansett, 36, a runner whose clot on a flight to Europe caused a disabling stroke.

The UK Department of Health recently advised air travelers to flex their legs at half hour intervals. During air travel blood flow slows down, especially in the lower legs, and coagulability rises steadily. Clots form in five to ten percent of passengers, usually in the calf (deep vein thrombosis, DVT), where they can cause swelling and pain which often becomes chronic. In some cases a clot moves to the lung causing pulmonary embolism (PE), producing pain, fainting and death.

New data shows that being athletic accounts for ten times more victims than any of the usual risk factors for blood clots, such as a previous blood clot. Forty-five athletic victims have contacted Airhealth.org, whose director, Michael Reynolds, says: "For every victim who has heard of us, there are probably a thousand who haven't." Dr. Robert McBane of the Mayo Clinic says that PE is the fourth leading cause of death in developed countries. Other experts say half of PE deaths are due to air travel.

Athletes with lower resting pulse rates have greater risk of stasis: stagnant blood subject to clotting. Another theory is that athletes are more likely to fly with bruises or sore muscles which can trigger clotting. Runners should wear compression stockings and flex their legs at fifteen minute intervals during flights. They also need to know how to recognize symptoms. See www.airhealth.org for more information on describing symptoms and tips on avoiding misdiagnosis, which usually aggravates the injury and increases the risk.

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